1,720,962 research outputs found
A high performance flexibility-based GBT finite element
No full textA new 2-node finite element for the Generalized Beam Theory is developed based on the hybrid complementary energy functional, involving nodal displacements and equilibrating stresses within the element as independent variables. Assumed stresses are rationally derived basing on the stresses associated to analytical solutions of some particular cases. Displacements within the element are a posteriori recovered by shape functions based on the same solutions. Numerical results show the high performance of the proposed element: generalized displacements and stresses are accurately predicted with very rough meshes, often using only one or two finite elements
Linearly elastic constitutive relations and consistency for GBT-based thin-walled beams
No full textThe present paper focuses on the constitutive assumptions, both for the isotropic and orthotropic cases, and consistency in the framework of the Generalized Beam Theory. In particular, a novel approach based on energetic arguments, able to automatically select appropriate constitutive relations in accordance with the GBT kinematics, is presented. Furthermore, the concept of consistency of a GBT-based model is established and a consistency analysis is presented. This yields a formal rational basis to investigate the effects of the various families of cross-section deformation modes in terms of predictive capabilities of the GBT model. Some numerical examples illustrate the arguments exposed in the paper
Buckling analysis of steel rack-section members by the gbt-based ecbl approach
No full textThe Erosion of Critical Bifurcation Load (ECBL) approach is a practical tool to characterize the instability behaviour of thin-walled cold-formed steel members. In this framework, the Generalized Beam Theory (GBT) is used to find (1) the interaction point of simultaneous buckling modes and (2) the erosion of the critical bifurcation load referred to this interactive buckling of two or more buckling modes associated with the same critical load. In this sense a modified version of the ECBL approach is proposed. Some numerical re-sults involving pallet rack uprights in compression are presented and compared with experi-mental ones, classical ECBL approach and EN 1993-1-3
A modified ECBL approach for cold-formed steel rack section members
No full textThe calibration of appropriate buckling curves for interactive local/distortional-global buckling of thin-walled cold-formed steel members is a task well covered by the Erosion of Critical Bifurcation Load (ECBL) approach. In this context, here a modified formulation of the ECBL approach, based on a new definition of the mode interaction point, is presented. The Generalized Beam Theory is used to find the mode interaction points and the related imperfections. Pallet rack uprights in compression are studied to show the potentialities of the modified ECBL approach and mark the differences with the classical one. The buckling curves coming from the modified ECBL approach are also compared with experimental results and with the buckling curves evaluated following the EN15512:2009
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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